中文摘要：

针对不对称半桥式功率变换器的主电路拓扑，通过理论分析和仿真实验，对变换器中的功率管短路和开路故障诊断进行研究。基于电压脉宽调制斩单管控制策略，分析变换器单相功率管故障情况下，斩波电流和续流电流的故障表现。通过改变电流传感器位置，提出一种基于直流母线电流和续流总线电流数字化信号的变换器故障在线诊断方案。故障模拟实验验证了所提方法的正确性和实用性。该方法相对于传统的三相电流检测方案，节省了传感器数目，可实现故障定位，具有诊断迅速、可靠性高的优点。

英文摘要：

Through analysis and simulation, the short- circuit and open-circuit fault diagnosis of transistors in the widely used asymmetric bridge converter were studied. Based on the voltage pulse width modulation （PWM） control strategy with single transistor chopped, the behavior patterns of chopping current and freewheeling current were analyzed under the single phase faults of power converter. An on-line fault diagnosis method using the digitalized DC bus current and freewheeling bus current was proposed by changing the current sensors＇ positions. The validity and practicability of the method was verified by simulated fault experiments. Comparing with traditional current detecting scheme, the proposed method could locate the fault easily and has the advantages of quick response and high reliability with less sensors.